What are the advantages of layers?

There are some real advantages to making use of layers when you are working inPhotoshop. A major benefit of layers is that they allow you to isolateindividual pieces of artwork and that means that you will be able to move andto edit the content of each layer independently without disturbing the rest ofthe image. For example, in this composition, I have the candies that you seehere on a separate layer as represented by the candies layer in the Layers panel.To show you the content of this layer alone I'll hold the Option key on a Macwith the Alt key on a PC as I click on the eye icon to the left of the candies layer, and that shows you in the document window that there is content on thislayer up here, and that the rest of the layer is transparent orsemi-transparent. I'll Option or Alt- click again on the eye icon to the left ofthe candies layer to make the rest of the layers visible.

Being able to move the content of this or any layer independently of the restof the image is an important benefit of using layers.To move just the candies for example, I first have to select the candies layerby clicking on that layer in the Layers panel. Then I'll go to the toolbox andI'll click on the very first tool, the Move tool, to select it. And thenI'll come into the image, I'll click anywhere and I'll drag. I'm going to drag up.And notice that I didn't have to click directly on the candies that wereshowing in order to move the content of this layer because when youclick-and-drag on a layer, the entire layer moves just one unit. When you dragwith the Move tool, if you want to constrain the direction of the movement sothat you don't inadvertently move left to right, if you're just trying to movedirectly then you can hold down the Shift key as you drag.

Notice that I push some of the content of the candies layer up off the top ofthe canvas. But that content isn't gone forever. If I want to get it back all Ihave to do is drag down in the other direction and it reappears. And that's trueeven if I were to save and close this image and then reopen it. I'm goingto drag the candies up again to show you that the stars are now noticeable ontop of the candies. That's because the candies layer is located beneath thestars layer in the stack of layers, and you can see that here if you look atthe Layers panel. Here's the candies layer and above it is the stars layer.

I'll have more to say on this subject of stacking order later in this chapter.Moving the content of layers independently is a huge benefit of using layers.But it's not the only benefit that layers offer. Just as important is the factthat I can edit the content of each layer independently of the rest of the image. And when I say Edit I'm referring to almost anything you can do tocontent in Photoshop from adding a style to a text layer to dodging or burning a photo layer.To give you just a taste of what I mean, I perform a simple edit on one of thelayers in this file. I'm going to select Layer 1 here, which is the layer thatI added as a new layer in the preceding movie. To show you what's on Layer 1I'll hold the Option or Alt key and click on the eye icon to the left of that layer, and you can see in the document window that this layer is composedprimarily of transparent pixels. But it does have this small pink brush strokeat the bottom of the layer, which I added in the last movie.

I'll go back to the layer and I'll Option or Alt-click on its eye icon to bringback the rest of the layers. Because I want to edit the content of just thislayer it's important to double-check that this layer is selected. In other words highlighted here in this Layers panel. I'll talk a lot more aboutselecting a layer in later movies. But now I'd like to show you one of the manythings that I could do to this layer without affecting the other layers. Solet's say for example, I want this pink stroke to be larger so it covers alittle more of this area down here at the bottom right.

To do that I'll use the Transform command in Photoshop. The most direct way totransform layer content is to select the Move tool, which I already haveselected in the toolbox, and then to go to the Move Tool Options bar up hereand check this box next to Show Transform Controls. That displays these anchorpoints around the contents of the selected layer. I can click on any of theseanchor points and drag to change the size and shape of this image. If I holddown the Shift key and click on one of the corner anchor points and then drag,that maintains the proportions of the original artwork as I resize it.

When I'm transforming bit-mapped or pixel-based artwork like this strokeI'm always careful not to make it too much bigger than the original or it willstart to get blurry and at some point of it will begin to actually display thepixels that make up that content.When I'm done I have to commit this transformation and to do that I'll go up tothe Options bar and I'll click the big check mark here on the right. And tomake the anchor points disappear down here I'm going to go to the Options barfor the Move tool and un- check Show Transform Controls.

The take-home point of what I just did is that the changes I made to this contentaffected only the pink stroke on Layer 1. They didn't affect any other part ofthis image, and there are lots of other manipulations that I could make to thislayer or to any layer without affecting the other layers in the file. I couldadd a filter, I could change the color of the content, I could add a layerstyle and lots more.You can start to see from the simple examples that I have showed you that beingable to move and edit individual pieces of artwork in isolation from the restof a Photoshop composition is a major benefit of using layers. I do want tomention that there are some other advantages of using layers that areassociated with special kinds of layers. To give you just one example I have atype layer in this file and a type layer is a special kind of layer, in partbecause it remains editable.

So even if I were to save and close this file and then reopen it, I couldchange the look or the content of this type layer. I'll be talking about typelayers in depth later also, but just to give you a quick look at how that would workI'm going to select the dreamy treats layer by clicking on that layer, andthen I'm going to go to the toolbox and I'm going to select the Horizontal Type tool. Then I'll come into the image, I'll click just to the right of the lastletter and drag over the other letters of that text. And now I'm going to typesomething different. I'll type sweet dreams and then I'll go up to the Options barfor the Type tool and I'll click the check mark to commit that edit.

That's just one example of an advantage associated with a special kind oflayer. Later in the course I'll be covering lots more about type layers andintroducing you to the advantages of other special layers including shapelayers, Smart Object layers and some special layers in Photoshop CS4 Extended,video layers and 3D layers.So that gives you a look at some of the advantages that layers offer. Increasein file size due to layers is becoming less-and-less of an issue, and it'soften outweighed by this serious power and flexibility that Photoshop layers offer.

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Released

5/15/2009

In Photoshop CS4: Layers in Depth, Jan Kabili explores the layer-related features and techniques that allow designers and photographers to work non-destructively with separate pieces of artwork, photographs, and text in a single Photoshop file. She teaches everything from the basics of creating and managing layers to more advanced topics like layer masking, layer comps, and clipping layers. Exercise files accompany the course.